Jamal Olasewere was having a typical freshman year, full of inconsistency and incredible potential, while struggling with the reality of playing for a losing team for the first time.

C.J. Garner could only watch, forced to sit out the season after transferring from South Alabama following his freshman year.

Things hadn’t gone according to plan and their future at LIU Brooklyn gave no more clarity. The Blackbirds were just another mid-major program off the grid, one without an NCAA Tournament appearance since 1997.

Three years — and three trips to the NCAA Tournament — later, the high-school teammates are trying to extend their college careers, vying for the program’s first-ever tournament win, against fellow 16th seed James Madison tomorrow night, hoping it won’t be the last game they play together.

“They’re like brothers. They needle each other, they get after each other, they’re funny that way,” LIU coach Jack Perri said. “It’s a love-hate relationship, but much more love than hate. They’re pretty unique and it’s made for a remarkable combination playing together. How fortunate were we over the past three years to have two kids that won’t allow you to lose?”

Olasewere, a 6-foot-7 forward and Northeast Conference Player of the Year, and Garner, a 5-foot-10 guard and NEC Tournament MVP, never envisioned playing together in college.

Eight years ago, they met at Springbrook High School in Maryland, where they led the Blue Devils to the state championship in 2008, rallying the team from 18 points down with eight minutes to go in the title game. The next year, Olasewere led Springbrook to another state title with an undefeated record.

“They never thought they could be beaten,” Springbrook coach Thomas Crowell told The Post. “One of them was going to step up and do something big and they always did. Every time. The confidence level in both of them, there’s nothing that either one of them think they can’t do.”

Garner went to South Alabama, a school to which Olasewere, who had drawn heavy interest from Georgetown and Xavier, never dreamed of going. But Olasewere never received official offers. Though then-LIU coach Jim Ferry had never watched Olasewere play, Perri, the longtime LIU assistant, was convinced he had seen a program-changing player.

“I was the only one who’d seen him live and I told Jimmy, ‘We’re taking this kid,’ ” Perri said.

When Garner decided to transfer, unhappy with South Alabama’s style of play and the departure of an assistant coach who recruited him, Olasewere put in a good word with LIU for his old friend.

“I always tell Coach Perri, I got him here,” Olasewere said. “I was the coach who recruited him … but to win together in high school and do it again in college, to be part of history and win so many championships, it’s crazy. It’s more than I could’ve imagined.”

The Blackbirds have gone 72-26 over the past three years, perfecting late-game poise and building a Brooklyn dynasty.

“No matter what it is, after that high school championship, we never think a game is over,” said Garner. “We pretty much have the same mentality. We have a real strong will to win. We talk about that. When it’s time for us to perform, when it’s a big stage, we come through.”

The duo’s days are numbered, in Dayton or beyond. And Perri knows he may never get so lucky again.

“It’s a little depressing, I try not to think about it because they’ve meant so much to this program and to me personally,” said Perri. “The growth they’ve had as people, as leaders and basketball players, they have a special piece of my heart. It’s going to be sad. It always is. They’re going to move on and have great careers, doing whatever they want to, but you’re not going to be able to replace those guys.”